Sliding Label with jQuery

I was using Sliding Label mooTools version for a while but when I had alot of jQuery scripts running up in one of my pages; it wasn’t that smart to include another library too.. obviously because it’s resource-consuming; so I wrote this small version for jQuery.

What is Sliding Label? an effect on input fields where the label slides out of it when the input gets the focus.. not clear enough? here is an example: